The present invention relates to a process for isotope separation by gaseous diffusion by means of porous barriers. More specifically, it relates to an isotope separation process making it possible to improve the operating conditions of a gaseous diffusion installation, particularly by reducing the energy consumed in such an above installation.
The presently known apparatus for the separation of isotopes by gaseous diffusion are generally constituted by an assembly of porous barriers in the form of microporous cylindrical tubes, within which is circulated in turbulent manner the gaseous mixture to be separated.
By passing through said tubes, the gaseous mixture is separated into a light isotope-enriched fraction which diffuses through the wall of the tubes, and a light isotope-depleted fraction which is discharged at the outlets from the tubes.
In view of the fact that passing through a porous barrier only leads to a very limited enrichment of the gaseous mixture, to obtain a significant enrichment by the light isotope, this operation must be repeated a significant number of times.
Therefore, a gaseous diffusion isotope separation installation generally comprises a large number of elementary stages grouped in cascade form, each elementary stage being constituted by an assembly of porous barriers.
In the most widely used type of cascade, the stages are grouped in such a way that the enriched fraction leaving the stage is passed to the following stage, whilst the depleted fraction leaving the same stage is passed to the preceding stage. Before being introduced into their respective stages, the enriched and depleted fractions leaving one stage must be compressed in order that their pressure is brought to the selected value for the diffusion.
Therefore, the energy necessary for the operation of such an installation and specifically the power which is more particularly consumed in the performance of the various compression stages is very high, due to the large number of stages.